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Specialized CG-R Carbon Seatpost



Unique looking carbon seatpost provides a smoother ride, though its looks won't be for everyone

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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If you want a smoother ride without the expense of buying a new bike, the Specialized S-Works CG-R carbon seatpost could be a really good option. It might look odd, but it provides a lot more flex than a regular seatpost and contributes to a more comfortable ride on poorly surfaced roads.

  • Pros: Provides additional comfort
  • Cons: Doesn't look too hot

A common sight on the Specialized Roubaix, a bike which was developed to tame the cobbled classics and rough roads, the CG-R seatpost is also available to buy separately. With a 27.2mm diameter, it'll fit most modern road, gravel and cyclo-cross bikes, and is an easy way to smooth your ride.

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The funky Cobra snake-shaped head is engineered to provide deflection through the unique shape and the carbon fibre layup. When the wheel hits a bump in the road the post flexes, allowing the saddle to move back. The range of movement is up to 18mm according to Specialized, though how much it flexes will likely come down to rider weight and how hard you're hitting the cobbles.


There's a Zertz elastomer bumper wedged into the top of the post, which is intended to damp the flex of the carbon post, but it's debatable how much it impacts the overall performance; it's not tuneable in any way to suit different road conditions and rider weights.

Fitting it to a bike was easy. It's a single-bolt saddle clamp, with a choice of cradles for round alloy and oval carbon saddle rails. There's plenty of angle adjustment to get the saddle in the perfect position.


The post is available in two lengths, 400mm and 350mm, which should be adequate for all.


Out on the road and the difference to a regular seatpost is noticeable straight away. You can even see the seatpost flexing when you look between your legs, though the range of movement is small enough that it's not like you're riding a bucking bronco when you hit a particularly bad patch of tarmac.

It really does help to deliver a smoother ride on those roads where the top layer of tarmac has been peeled away, and when you hit the edge of a hole or crack. It doesn't filter out everything – it's not like riding a full suspension mountain bike – but it's enough to remove the harshness.

> 9 ways to make your bike more comfortable

I can't confirm that you get the 18mm claimed vertical compliance, but I'm a light rider (64kg at the time of writing this) so that could influence how much the post flexes. Bigger cyclists will probably get more movement out of the CG-R. (There's no rider weight limit to worry about.) Also, the amount of setback seems to make a difference too; I set my saddle up somewhere in the middle of the rails.

Cheaper than buying a new bike, the CG-R seatpost might cost more than a regular seatpost – though it's £95 less than the Enve Carbon seatpost I've also reviewed – and is a really easy choice to make if you crave a bit more comfort.


Unique looking carbon seatpost provides a smoother ride, though its looks won't be for everyone

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Make and model: S-Works CG-R Carbon Seatpost

Size tested: 27.2mm x 350mm

Tell us what the product is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

Specialized says, "The CG-R seatpost extends the concept that 'Smoother is Faster.' This revolutionary post features 18mm of vertical compliance, Zertz vibration damping, and FACT carbon construction. The CG-R delivers unsurpassed comfort, control, and efficiency without adding weight or complication to the frame. No matter what surface your ride takes you on, the CG-R will make it better"

Tell us some more about the technical aspects of the product?

From Specialized:

Revolutionary design allows 18mm of vertical compliance

FACT carbon construction blends durability and comfort

Vibration-damping Zertz for increased comfort

Cylindrical Aluminium head assembly adjusts fore-aft and tilt with an easy-access single bolt

Diameter: 27.2mm

Length: 350mm

Rate the product for quality of construction:
Rate the product for performance:

Delivers a smoother ride than a regular seatpost; might work better for heavier riders and bigger impacts though.

Rate the product for durability:

Not had any problems so far, and I've used it on a gravel bike to really pound it hard.

Rate the product for weight (if applicable)

Not an unreasonable weight given its benefit over a normal post.

Rate the product for comfort (if applicable)

It's more comfortable than a regular carbon seatpost.

Rate the product for value:

It's not cheap, but it's cheaper than buying a new bike...

Tell us how the product performed overall when used for its designed purpose

Delivers a smoother ride over really rough roads and works on gravel and adventure rides too.

Tell us what you particularly liked about the product

Easy to fit and provides a smoother ride.

Tell us what you particularly disliked about the product

Doesn't look great – but you can't see it when you're sat on the saddle!

How does the price compare to that of similar products in the market, including ones recently tested on

It's cheaper than an alternative like the Canyon VCLS 2.0 post (rrp £226.95).

Did you enjoy using the product? Yes

Would you consider buying the product? Yes

Would you recommend the product to a friend? Yes

Use this box to explain your overall score

It does its job of smoothing rough roads really well, and while it isn't 'cheap', it costs less than a new bike – and a number of seatposts.

Overall rating: 8/10

About the tester

Age: 31  Height: 180cm  Weight: 67kg

I usually ride:   My best bike is:

I've been riding for: 10-20 years  I ride: Every day  I would class myself as: Expert

I regularly do the following types of riding: road racing, time trialling, cyclo-cross, commuting, touring, mountain biking

David worked on the tech team from 2012-2020. Previously he was editor of and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds, and you can now find him over on his own YouTube channel David Arthur - Just Ride Bikes

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Richard D | 5 years ago

Ditto to both previous comments.  I’ve been using one for three or four years, and it’s comfy (as comfortable as switching from 23s to 25s?).  And it cal also creak to buggery.

Geordie Simon | 5 years ago

Can creak like hell if you don't keep the clamping mechanism greased....

NorthEastJimmy | 5 years ago

Can definitely recommend this seat post as Ive been using one for the last 3 years and much prefer my rides on the bike that has this over the one with the normal seat post.

I have noticed that very rarely (maybe only a handful of times a year) that if the vibrations from the road surface resonate in a certain way through the seat post, it can feel exactly like your rear tyre is getting a puncture! Not that annoying though once you realise all is fine.

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